X-bar in statistics is a symbol for the sample mean. Given a sample of n observations of numbers, the sample mean is found by adding up all of the observations, then dividing by the total number ...

Learn how to write hypotheses for a significance test for a mean, and see examples that walk through sample problems step-by-step for you to improve your statistics knowledge and skills.

Get help with your P-value homework. Access the answers to hundreds of P-value questions that are explained in a way that's easy for you to understand. Can't find the question you're looking for? Go …

Statistic and Symbols: All science deals with variables and their characteristics, including statistics. For example, measures of central tendency and dispersion of samples and populations are written with …

Learn what sigma is, understand its origin, and discover what it represents in mathematics. Explore the meaning of sigma as summation and the...

Learn about reliability and the reliability coefficient. Explore the calculations for and types of reliability, along with the applications of each...

Understand what an alternative hypothesis is and see alternative hypothesis examples. Learn how to write it and what is meant by ruling out the...

Understand what a point estimate is. Learn the point estimate definition, the point estimate formula and symbol, and how to find point estimate through examples.

When to Use t-Test Formula T-tests can be used in both statistical experiments and correlational studies. Different types of t-tests exist depending on the number of means being compared.

One-tailed tests are more common when showing statistical power in one direction. Two-tailed tests are more common when showing statistical power between two groups.